Stroboscope



March 6, 1934. s. LIVINGSTON 1,949,483

STROBOSCOPE Filed March 6, 1951 lNV NTOR as 3W Patented Mar. 6, 1934 UNITED STATES PATENT OFFICE This invention relates to high tension electrical discharge apparatus, and particuarly to stroboscopes.

It is well known that lamps giving a momentary illumination are used for viewing moving objects. These lamps are usually energized for causing them to become illuminated periodically in synchronism with the movement of the moving body viewed. The effect, as well known, is to give the illusion of a stationary body. Such devices are known as stroboscopes.

A common form of lamp, used as a stroboscope, is the well known neon tube or lamp. When such a lamp is used, it is necessary, in order to increase the quantity of light, to increase the voltage,-but where transformer or induction coils are used it is necessary to keep the voltage of the secondary coil down to a value which obviates a self induction sufiicient to cause an undue persistence of the glow in the neon tube. This persistence, destroying definition, prevents the free increase of illumination simply by increasing the electrical dimensions of the secondary of the transformer used. I

If a plurality of secondary coils are placed upon one primary and each secondary is used to energize a separate and independent neon lamp, then the result is that the neon lamp which breaks down at the lowest voltage has a discharge therein whereas the other neon lamp has no discharge therein.

If a plurality of neon lamps connected in parallel across one secondary is used, then the result is that one lamp of the plurality breaks down and there is no discharge through any of the other lamps. v

If two or more neon lamps are connected in series across the terminals of one secondary, then the result is that as the voltage is raised to provide the necessary breakdown voltage for the lamps in series to obtain the maximum illumination, definition is/ impaired because the high self inductance causes a persistence of the flash which is virtual 1y equivalent to 'a perceptible movement of the body moved while being illuminated, so the ,result is that the motion is not ..stopped.

A- principal object of applicants invention is to provide means and method whereby amofe' intense illumination may besecured in a stroboscope without impairing the definition.

A 1 her object of applicants invention is to provide means for causing a maximum of illumination with a maximum of definition in a stroboby providing means whereby a discharge simultaneously occurs in a plurality of neon lamps and of a duration short enough to give a proper and desirable definition.

Other objects and advantages the description of the particular means selected 50 to illustrate the invention progresses, and the novel features of the invention will be particularly pointed out in the appended claims.

In describing the invention in detail and the particular physical embodiment selected to il- 55 lustrate the invention, reference will be had to the accompanying drawing and the several views thereon in which like characters of reference designate like parts throughout the several views, and in which:

Figure 1 shows diagrammatically a plurality of neon lamps, a transformer associated with each lamp, each transformer including a primary winding,- and a single make and break contact or current interrupter in a series circuit including all of the primary coils; Fig. 2, illustrates diagrammatically the insertion of a rheo- Stat in one of the wires of the arrangement as shown in Fig. 1.

In the drawing, numeral 1 designates an arm pivoted at 2 and spring 3 positioned to engage contact 4 or become disengaged therefrom in accordance with the position of the protuberance 5 ,on cam 6 'mounted on and rotatable with the rotatable shaft '7.

The make and break device or current interrupter including arm 1 and contact 4 are included in an electrical circuit as follows: battery or source of potential 8, wire 9, primary coil 10 of a transformer, wires 11 and 12, primary coil 13 of a transformer, wires 14 and 15, primary coil 16 of a transformer, wires 17, 18, and 19, contact 4, arm 1 and wires 20 and 21 to the other terminal of the source of potential or battery 8.

Shaft '7 and cam 6 may be rotated by any suitas able or proper means. In practice, the cam 6 is usually rotated, if possible, by a part of the machine which it is intended to view with the stroboscope, but if the operation of the cam by the machine would interfere with the proper 10 operation thereof, then a separate and independent motor of some sort would be used to operate the cam 6. Whatever method is used,

will appear as the cam 6 would, rotate synchronously with the moving body to be viewed by the stroboscope 5 and the circuit interruption caused by the cam would occur at such times as would enable an observer to view the proper part desired by the illumination of the stroboscope. In the particular arrangement shown in the drawing each of the primary coils as 10, 13 and 16 has associated therewith the usual iron core as 22, 23 and 24 respectively, and in addition each has associated therewith a secondary coil as 25, 26 and 27 respectively. One terminal of each secondary coil is connected to a terminal of a high tension discharge or neon tube. Coil 25 is connected to terminal 28 of neon tube 29;

coil 26 is connected to terminal 30 of neon tube 31; coil 27 is connected to terminal 32 of neon tube 33. The other terminals of each of the neon tubes as 34, 35 and 36 are each connected to a common return wire 37.

When cam 6 rotates, the circuit through 1 and 4 is alternately made and broken so that the circuit through primaries 10, 13 and 16 is alternately made and broken and consequently a voltage or difference of potential is generated in coils 25, 26 and 27 and simultaneously a discharge takes place in'neon tubes 29, 31 and 33. The illumination from all of these tubes may be concentrated upon theparticular part to be observed by the use of any common and well known means by which light from several sources is concentrated upon one point or object.

Although applicant has shown three tubes only and three transformers only, nevertheless, it is desired to have it understood that the number of tubes and the number of transformers is merely a matter of volition.

Although applicant has shown three separate and independent neon tubes energized by the three secondaries, it is to be understoodthat applicant does not intend to exclude a construction in which one neon tube only is used constructed with a plurality of terminals at one end, in this casethree, and one terminal at the other end, in which the common terminal of the three secondaries will be connected to the one terminal at the one end and the other three terminals will be connected each to a different secondary terminal.

In Fig. 2 a rheostat has been illustrated inserted in the wire 21. This rheostat has the usual resistance coils 38 and the movable conducting arm 39. When such a rheostat is inserted in the wire 21 in Fig. 1 then it is possible to 'vary the E. M. F. impressed upon the primaries 10, 13 and 16. If a large E. M. F. is impressed upon these coils, then there is a large current flow and consequently the self induction is greater and the dying out of the glow in the neon tubes is slower. When the E. M. F. impressed upon the primaries is relatively lower the self induction is less and the persistence of glow is shorter. If a relatively slow moving body is being observed, a greater persistence of glow may be allowed without impairing definition than if the motion is relatively rapid, so that when the motion is relatively slow increase of illumination is obtained by increasing the impressed E. M. F. on the primaries, but with this increased illumination there is some slight decrease of definition but not enough to be unduly objectionable. When extremely rapid motion is being observed, then the impressed E. M. F. is decreased so that although the maximum of illumination is not obtained a maximum of definition is obtained be-. cause the glow does not persist so long. By taking advantage of the phenomena, hereinbefore described, and operating the stroboscope in accordance with the teachings thereof, a method is provided which gives satisfactory results both with relatively slow and with relatively rapid motion.

Although applicant has illustrated and described a rheostat as a means for altering the impressed E. M. F., nevertheless, it is desired to have it understood that applicant does not by such showing and description intend to exclude other and well known means of attaining the same result, that is, the alteration of the impressed E. M. F. upon the primary coils when aconstant source of potential such as 8 is employed, and so an alteration in the current.

Although I have particularly described one particular physical embodiment of my invention and explained. the. principle and mode of operation thereof, nevertheless, I desire to have it under stood that the form selected is merely illustrative, but does not exhaust the possible physical embodiments of the idea of means underlying my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

As a stroboscope, the combination of a plurality of high tension electrical discharge tubes, a plurality of transformers, each including a primary winding and a secondary winding, a source of potential, and a circuit interrupter, all of the primary coils, the source of potential, and the circuit interrupter being connected in a series circuit, and each of the high tension discharge tubes being energized by one only of the secondary coils.

STANLEY'D. LIVINGSTON. 

